Disclosed is a circuit for compensating for an offset voltage of a monitoring photodiode. After the offset voltage is measured in a photodiode test, current source and offset resistors are added according to the measured resistances, thereby compensating for the offset voltage.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An offset compensation circuit, comprising: an amplifying element for amplifying an input signal and outputting the signal; a power unit comprising: a main current source connected to an input terminal of the amplifying element; at least one additional current source connected to the main current source in parallel; and a switching unit, correspondingly connected to the additional current source, for switching the additional current source to at least one of on and off to increase the offset voltage of the amplifying element in a discrete pattern; and a feedback resistant element connected between a different input terminal and an output terminal of the amplifying elements.
2. The offset compensation circuit as set forth in claim 1 , wherein the switching unit comprises: a fuse; and a switching pad, connected to both ends of the fuse, for supplying a large quantity of a current therethrough to disconnect the fuse.
3. The offset compensation circuit as set forth in claim 1 , wherein the switching unit comprises switching elements to switch on and off according to input signals, and an offset control block for selectively switching the switching elements on and off to increase the offset voltage of the amplifying element in a discrete pattern.
4. The offset compensation circuit as set forth in claim 1 , wherein the switching unit comprises: switching elements that switch on and off according to input signals; a sensor for sensing an output voltage of the amplifying element in synchronization with the offset control block and providing the output voltage to the offset control block; and an offset control block for switching the switching elements on and off according to the sensed values.
5. An offset compensation circuit, comprising: an amplifying element for amplifying an input signal and outputting the signal; a resistor comprising: a main resistor connected to an input terminal of the amplifying element; at least one additional resistor connected to the main resistor in parallel; and a switching unit, correspondingly connected to the additional resistor, for switching the additional resistor to at least one of on and off to decrease the offset voltage of the amplifying element in a discrete pattern; and a feedback resistant element connected between a different input terminal and an output terminal of the amplifying element.
6. The offset compensation circuit as set forth in claim 5 , wherein the switching unit comprises: a fuse; and a switching pad, connected to both ends of the fuse, for supplying a large quantity of current therethrough to disconnect the fuse.
7. The offset compensation circuit as set forth in claim 5 , wherein the switching unit comprises switching elements that switch on and off according to input signals, and an offset control block for selectively switching the switching elements on and off to increase the offset voltage of the amplifying element in a discrete pattern.
8. The offset compensation circuit as set forth in claim 5 , wherein the switching unit comprises: switching elements that switch on and off according to input signals; a sensor for sensing an output voltage of the amplifying element in synchronization with the offset control block and providing the output voltage to the offset control block; and an offset control block for switching the switching elements on and off according to the sensed values.
9. An offset compensation circuit, comprising: an amplifying element for amplifying an input signal and outputting the signal; a power unit comprising: a main current source connected to an input terminal of the amplifying element; at least one additional current source connected to the main current source in parallel; and a switching unit, correspondingly connected to the additional current source, for switching the additional current source to at least one of on and off to increase the offset voltage of the amplifying element in a discrete pattern; and a resistor comprising: a main resistor connected to an input terminal of the amplifying element, said input terminal being identical to that connected to the main current source; at least one additional resistor connected in parallel to the main resistor; and a switching unit, correspondingly connected to the additional resistor, for switching the additional resistor to at least one of on and off to decrease the offset voltage of the amplifying element in a discrete pattern; and a feedback resistant element connected between a different input terminal and an output terminal of the amplifying element.
10. The offset compensation circuit as set forth in claim 9 , wherein the switching unit comprises: a fuse; and a switching pad, connected to both ends of the fuse, for supplying a large quantity of current therethrough to disconnect the fuse.
11. The offset compensation circuit as set forth in claim 9 , wherein the switching unit comprises switching elements that switch on and off according to input signals, and an offset control block for selectively switching the switching elements on and off to increase the offset voltage of the amplifying element in a discrete pattern.
12. The offset compensation circuit as set forth in claim 9 , wherein the switching unit comprises: switching elements that switch on and off according to input signals; a sensor for sensing an output voltage of the amplifying element in synchronization with the offset control block and providing the output voltage to the offset control block; and an offset control block for switching the switching elements on and off according to the sensed values.
13. An offset voltage compensation method, comprising the steps of: measuring an offset voltage of an amplifying element for receiving an input signal and amplifying the signal, which is connected with at least two current sources in parallel and at least two resistant elements in series through its one input terminal and with a feedback through a different input terminal and an output terminal; determining whether the measured offset voltage is in an operation range; and selectively inactivating the current sources and the resistant elements according to the measured offset voltage so as to increase or decrease the offset voltage.
14. The offset voltage compensation method as set forth in claim 13 , wherein fuses are connected in parallel with the current sources and in series with the resistant elements, and the selective inactivation step comprises the selective application of a high intensity current across the fuses to selectively disconnect the fuses.
15. The offset voltage compensation method as set forth in claim 14 , wherein fuses are connected in parallel with the current sources and in series with the resistant elements, and the selective inactivation step comprises the selective irradiation of a laser beam onto the fuses to selectively disconnect the fuses.
16. The offset voltage compensation method as set forth in claim 14 , wherein switching elements are connected with both the current sources and the resistant elements, and the selective inactivation step comprises selectively switching the switching elements to at least one of on and off.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 9, 2005
April 24, 2007
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